Lamp



FIG. 1 is a perspective view of a lamp showing my new design;

FIG. 2 is a front view thereof, the rear view, right-side view, and the left-side view being identical; and,

FIG. 3 is a top view thereof.

The broken lines in the drawings represent environmental subject matter and form no part of the claimed design. 

The ornamental design for a lamp, as shown and described. 